DaveL59

decided what the heck and mounted one in the drill chuck and ran it holding a file against the knurled section. Elf and safety would've been unimpressed but...

Result, thanks Mark for that suggestion, stirred me to try it having dismissed the idea when I though of it earlier so you saying the same added reinforcement and saves having to order a replacement 🙂

Fine focus now locks when I need it, I'll look at ageing the brass at some stage depending on the experimental results with the M2 csk screw head.

Hmmm looking at the pic, decided to try a different mod with a round file:

That's much better 🙂 

1 minute ago, MarkAR said:

Maybe file a chamfer on the knurled bit thats in the way. 

Had thought that, or even grind into the silver ring to let it clear, but I think better to get a replacement with longer threaded section as there will be less to grip once clamped in a further 3mm. Not so bad now but on a cold night... 

There is a larger M3 tapped thumb wheel I can get from the UK, 15mm dia which might work ok with a nylon M3 screw inserted:

Kinda baulked at the £5 plus postage cost tho 😉 Could order a pack of 4 of this type for less than half the price and have spares

2 hours ago, Rustang said:

Photo attached, no obvious screws on the outsids, dew shield slides on and off the outside which has black felt around it, I don't believe that is covering any screws. 

Short of lifting the felt to see I can't really advise, not having one to examine. Hopefully someone else here may know more and comment. For sure I'd not disturb the lens ring until certain that's the way to remove the cell. Might be easier to remove the focuser and work carefully from that end, a long thin paint brush with lens cloth might reach and also act as a pressure control against the lens. You likely won't be able to reach your hand down the OTA as it'll have baffles I expect.

so feeling a bit more able today and sticking with the light duties theme, decided I'd drill and tap the M3 hole for the fine focus lock thumb screw and also another in the diagonal so the eyepieces can be clamped - original for the diagonal was lost and the original threaded hole wasn't holding the screw as the first part of the thread was damaged. Small pilot hole then drill out to 2.5mm and hand tap and...

Wow tapping that brass with an M3 was surprised how squeaky it went even with a drop of oil! Here's the result, with the M3x8mm thumb screws that arrived the other day. Not quite a match but they can be aged. I so need to get a pillar drill if I'm going to be doing a lot of this tho as both are at a little of an angle but what the heck, not bad for hand-holding the drill and part and it does work which was the object of the exercise 🙂 (well the fine focus one will do eventually that is lol)

So nearly there but... on the drawtube the knurled part snags that silvered ring before it can go far enough. Should've been braver and drilled closer to the edge, maybe. But no worries, I've ordered some M3x16mm black nylon until I can sort some longer brass ones which it looks like I'd have to order via Ali since nobody in the UK seems to list them at the moment. Likely I'll fill that redundant hole later on too.

I did consider some vintage spark plug terminal nuts with a nylon screw glued in as they are a closer match to the original brass/nylon one on the focuser but those seem to be M4...

Being only 5mm between the silver ring and the edge I wasn't so keen to run a M4 thread there at this stage. Wonder if I can use that idea tho and re-work the nylon screw to reduce M4 down to M3 below the nut and not have it shred while running a regular die over it or  it just snap off in use?

I've also got some brass pan-head's ordered to replace the 2 screws on the OTA that are currently CSK, so they fill the hole in the leather a little better.

Still experimenting with ageing the screw head, acetone and heat in the gas flame to remove any lacquer and then I've inserted the screw into some tin foil, tape on the thread so it doesn't fall in and sat that over the top of a small bottle with malt vinegar in it. Leave for as long as necessary and it does seem to be gradually ageing the finish. Seems the acidity of the fumes is more effective than immersion, will show results if I succeed.

Dismantling the diagonal while working on that new tapped hole, discovered that it's a prism not a mirror which I hadn't realised the old 60's Japanese scopes came with. I guess that's handy though as it won't have deteriorated over all these years, very neat.

if the main objective elements carry a mark on the edge it's best to align these when assembling it as that'll be where the maker found the best performance of the 2 elements combined to be.

I do similar to what Mark suggests on Bino's that I don't want to disturb the objectives or where the lens ring won't shift, tho if you do then use a very light touch so as not to scrape the dust across the lens.

I don't know the scope but the lens cell isn't retained by screws in the side of the OTA? If it is then the cell would come out complete and you could clean and re-fit and not affect the lens orientation or spacing. A lens ring may well be what is holding the lens in the cell and then you risk them coming out as separate lenses and have to orient and get the spacers placed when you reassemble. A pic of what you are looking at would help in terms of asking advice sp we know we're talking about the same things.

Gave the diagonal and eyepieces a wee daytime test now there's a bit of sun lighting up the distant tree branches. For sure very dim at 6 and 4mm but was able to make out what I was looking at. Nice clear image with the H20 and the MA40/original brass. Went from a branch and leaves to a leaf or 2 filling the FoV. Nice thing was the small eyepieces and diagonal don't seem to cause the fine focus to slip but the MA40 and original brass do of course, being much heavier and taller. I do think I'll need to fit a lock screw for the fine focus so I can re-lock the diagonal without losing focus and of course it'll be a touch fiddly to get the fine focus as that'll rotate the diagonal but it is what it is... Alternate might be to add a means to rack the drawtube without adding a rack to it but that seems too much faff.

Original brass plossl

and one of the smaller EPs

Am considering what to do with the finder, strip the paint on the foot and heat to apply a brassing effect (brass wire brush method) and re-paint the finder itself in black, perhaps.

so while I'm on "light duties" I thought I'd have a go to age the brass screw head. First try was malt vinegar and salt which had a little effect but seemed to not make much of a change after a few hours in the mix. Perhaps it might if left long enough. Should mention first step was soak in acetone to remove any finish protector. Certainly some effect as the threads turned pink, not the effect I was looking for tho.

Then I tried some balsamic vinegar and salt and even heating on the gas flame and hot dipping it. Some effect but not very dark. Read a tip that mentioned flux, of course now I want it I can't find the plumbers flux but I do have a flux pen for electronics work, so try that and see... has made a change but still not quite what I'm looking for:

I also swapped out the small steel CSK screw in the leather section for new brass, the M2 holds perfectly tho I might get a M2 cheese/pan head for this one later on.

Interested to hear any other thoughts on ageing/patina on new brass. Meantime I've another screw head undergoing just the flux treatment which I'll let age over a day or so and see how it does.

sounds interesting. These Nitrile caps are steel so would take a bit of work to cut. You'd also need to consider how to keep the nitrile secure on the uncut areas I guess, if is loses the bonding. I asked about the ID before buying as I recall, or found a supplier that listed the info. It's a very snug fit on the end of the TAL-M OTA and I use it for the mirror end since mine was missing both caps. The nitrile coating meant it doesn't mark the paint which is handy.

Good luck finding a solution and with the project  

might have been me Mark as I did get one for the TAL-M a while back. I think they're also referred to as a bearing end cap and are solid. The nitrile helps it grip the tube well too.

Only thing I'd ask Chris - out of curiosity, what are you thinking to mount using an end cap?

This morning the postie dropped a couple things off:

Many thanks Roy for the 0,965 eyepieces and diagonal which will give the scope a degree of range of magnification without modifications. Well I will need to add a lock screw to the fine-focus mechanism but I'll organise a brass thumbscrew for that so it looks in keeping with the vintage 🙂 

The Vivitar lens cap is metal, felt lined on the inner lip and a perfect fit over the brass dew shield, result!

Lastly the M2 CSK brass screws - one needed to secure the lens cell parts together. Hopefully it'll age to blend in, or I'll maybe clean and polish up the dew shield to bring it back to its former glory.

some bits for the vintage scope, diagonal and eyepieces courtesy of a member here, many thanks Roy!

I fitted a tripod plate under my little NatGeo which is very similar to your SW pictured. Downside it, not so stable on the Velbon photo/video tripod I have really. partly I think down to not a wide enough area supporting the base. It might be more stable on one of the scope tripods but then that adds bulk to shift. With mine the OTA doesn't have a dovetail, there's a captive bolt that fits into the upright that forms the DEC axis. Not sure what other good options there are other than a tall stool to sit it on, as you have done  

Been tempted by a small Cat myself John for the same reason, easy travel esp where mine are all long scopes in the main, just need to build some funds first tho...

yeah that's the problem, swap both or have a mis-match. The drawback of rescuing vintage gear sometimes. I think the ones I have on the spares have a screw on eyecup on the eyepiece body and a couple of those missing. Just loathe to chuck something that may yield spares for something later on hence they're sat in a box upstairs

Hi Mark, they do seem to vary between makers and models even. The there's matching the threads, not sure if those would be imperial and the japanese ones metric, for example, tho a german sounding make could be metric too. I've a few spare zenith 10x ZCF's kicking around spare in various condition so its possible and eyecup from one of those may work, post up the various dimensions and I can take a look at some stage, could be a bit slow on that tho...

On 21/07/2020 at 12:42, andrew s said:

Enough already, but where do you stand on the rigid foam v cardboard inserts v poly chips v bubble wrap great debate?

Does it split opinion like refractor v reflector?

Show us your stuffing.

Regards Andrew 

tis a shame they don't do the nice wood inserts to hold everything tho like in the boxes of old, Tal and the older japanese scoped. The polystyrene while light and moulded to fit soon falls to bits with regular repacking and removal where the wood only needs the foam/felt renewed and it lasts a good many more years

might as well join in, tho I did collect these certainly the cardboard one would have been the shipping box for the 100RS and from what I've read the TAL wood boxes were used to ship the scopes...

so yep, more than 10 years here, the wood box is 1996 and the card one unknown but more than 10 years, I think it was from 2003 or earlier.

yep that sure won't help. If you can get some self-adhesive flocking and stick that around the inside of the dew shield that'll make a big difference in daytime use. At night unless it's the moon you should be ok though, unless there's lights in the area that may reflect.

do you get better views looking at a target with the sun behind you?

To improve the light damping inside the scope will mean dismantling it and trying to insert a flocking material which on a narrow tube could be quite fiddly. Also check the eyepiece and diagonal barriers are matt black inside the barrel part or they will add to the reflections. For looking at the stars though, you may be fine as it is so give that a try first. 

5 minutes ago, MarkAR said:

The old brass one is quite possibly a BA thread.

yep am thinking that too, tho I don't have any BA taps these days and not one that small when I did as those were for car repairs so long since retired and disposed (foolish boy!). I may see how an M2 will hold and if not re-tap to m2.5 or M3 if I can source suitable screws, M3 countersunk have a deeper taper so may not sit well, don't want to lose threads off the inner tube as it's not that thick. On the OTA a dome head would work as it'd still sit below the leather surface, could go brass to highlight or black to blend and disappear I guess. For the shield defo brass so it fits with its surroundings.

Is the direction you are looking toward where the sun is? or in that side of the sky?

Could be internal reflection if the tube isn't well flocked/coated to damp down the stray light and it's reflecting around inside the tube. That'll certainly lose contrast much as it does with binoculars or even sunglasses.

+1

also give a try without the diagonal to eliminate that as the cause.

A wet tissue isn't ideal, lens cleaner (glasses type even) is much better, but the diagonal definitely not. It'd need the mirror cleaning with mild soapy water and rinsed with distilled water and left to dry to not damage the surface. 

Decided it might be smart to secure the lens cell even tho I don't have a suitable brass countersunk at the moment, since they do rotate fairly easily, better safe and all that. So drilled and tapped for M2 and countersunk the brass side a little. I'll order some M2x6mm countersunk brass screws and finish the job later on.

The screw that holds the cell to the body could well be an older imperial thread, since the M2 fits, seems to hold but is a touch loose perhaps. That original screw doesn't seem to fit the M2 thread. Pity as I was thinking to make that brass too, as well as replace the one holding the focuser which is a longer M4 ish size.

While fiddling, decided to compare the brass eyepiece with the 1.25-inch ones I have, so sat the baby NatGeo 76/350 on the table and swapped them around. Luckily I have a 1.25-0.965 adaptor which made that easy. Seems to give an equivalent view as the TAL 25mm mk2 plossl just a touch narrower, but maybe not as much as the vixen 20mm compared the the TAL 25mm.

So I guess that old brass plossl (at a guess, not taken it apart yet) is around the 23-25mm mark, performs very nicely as well as being very nicely made. The more I play about with this old scope the more I'm liking it 😄 

yes, watched on the B&W TV in fascination and wonder. I was already interested in the planets but no scope to use. Was beyond our means I expect, being one of 3 kids, plus all the travelling every couple years it'd have gotten wrecked in transit. Pity really as we may well have been able to pick up a quality japanese scope back then being in the far east at the time.

And I'll add my birthday wishes to you too Gina, many happy returns! 🙂